2021 CITROEN C4 AIRCROSS DAG check engine

87
Driving
6Before setting off
Nose weight
► Distribute the load in the trailer so that the heaviest items are as close as possible to the
axle and the nose weight (at the point where it
joins your vehicle) approaches the maximum
permitted without exceeding it.
Tyres
► Check the tyre pressures of the towing vehicle and of the trailer, observing the
recommended pressures.
Lighting
► Check the electrical signalling on the trailer and the headlamp beam height of your vehicle.
If a genuine CITROËN towing device is
used, the rear parking sensors will be
deactivated automatically to avoid the audible
signal.
When driving
Cooling
Towing a trailer uphill causes the coolant
temperature to increase. The maximum towable
load depends on the gradient and the exterior
temperature. The fan’s cooling capacity does not
increase with engine speed.
► Reduce speed and lower the engine speed to limit heating up.
In all cases, pay attention to the coolant
temperature.
If this warning lamp and the STOP
warning lamp come on, stop the vehicle
and switch off the engine as soon as possible.
Brakes
Braking distances are increased when towing a
trailer. To avoid overheating the brakes, the use
of engine braking is recommended.
Side wind
Bear in mind that the vehicle will be more
susceptible to wind when towing.
Anti-theft protection
Electronic immobiliser
The keys include an electronic engine
immobiliser system, whose secret code must be
recognised in order for starting to be possible.
If the system malfunctions, indicated by the
display of a message, the engine will not start.
Contact a CITROËN dealer.
For safety and theft protection reasons,
do not leave your electronic key in the
vehicle, even when you are close to it.
It is recommended that you keep it with you.
Starting / Switching off the
engine with the key
Key ignition switch

It has 3 positions:– 1. Stop : inserting and removing the key,
steering column locked.
– 2. Ignition : steering column unlocked, ignition
on, Diesel preheating, engine running.
– 3. Starting.
Avoid attaching heavy objects to the key or the remote control. It would weigh
down on its shaft in the ignition switch and
could cause a malfunction.
Ignition on position
It allows the use of the vehicle's electric
equipment or portable devices to be charged.
Once the state of charge of the battery drops to
the reserve level, the system switches to energy
economy mode : the power supply is cut off

88
Driving
automatically to preserve the remaining battery
charge.
Starting the engine
With the parking brake applied:► With a manual gearbox, place the gear lever
in neutral then fully depress the clutch pedal.
► With an automatic gearbox, place the gear
selector in mode N or P then fully depress the
brake pedal.
► Insert the key into the ignition switch; the system recognises the code.► Unlock the steering column by simultaneously turning the steering wheel and the key.
In certain cases, you may have to apply
significant force to move the steering
wheel (wheels on full lock, for example).
► With a petrol engine , operate the starter
motor by turning the key to position 3 without
pressing the accelerator pedal, until the engine
starts. Once the engine starts, release the key.
With petrol engines , after a cold start,
preheating the catalytic converter can
cause noticeable engine vibrations for anything up to 2 minutes while stationary with
the engine running (accelerated idle speed).
► With a Diesel engine, turn the key to position
2, ignition on, to operate the engine preheating
system.
Wait until this warning lamp goes off in the instrument panel, then operate the starter
motor by turning the key to position 3 without
pressing the accelerator pedal, until the engine
starts. Once the engine starts, release the key.
In wintry conditions, the warning lamp
may stay on for a longer period. When
the engine is hot, the warning lamp does not
come on.
If the engine does not start straight away,
switch off the ignition. Wait a few
seconds before operating the starter motor
again. If the engine does not start after a few
attempts, do not keep trying - risk of
damaging the starter motor and the engine.
Contact a CITROËN dealer or a qualified
workshop.
In mild conditions, do not leave the
engine at idle to warm up but move off
straight away and drive at moderate speed.
Switching off the engine
► Immobilise the vehicle.► With the engine at idle, turn the key to position 1.► Remove the key from the ignition switch.► To lock the steering column, turn the steering wheel until it locks.
To facilitate unlocking of the steering
column, it is recommended that the
wheels be returned to the straight ahead
position before switching off the engine.
Never switch off the ignition before the
complete immobilisation of the vehicle.
With the engine off, the braking and steering
assistance systems are also cut off - risk of
loss of control of the vehicle!
Check that the parking brake is correctly
applied, particularly on sloping ground.
When leaving the vehicle, keep the key in
your possession and lock the vehicle.
Energy economy mode
After the engine has stopped (position 1. Stop),
for a maximum combined duration of about thirty
minutes, you can still use functions such as the
audio and telematics system, courtesy lamps,
windscreen wipers, dipped beam headlamps,
etc.
For more information on Energy
economy mode, refer to the
corresponding section.
Key left in
When opening the driver's door, an alert
message is displayed, accompanied by an
audible signal, to remind you that the key is still in the ignition switch at position 1 (Stop).
If the key has been left in the ignition switch
at position 2 (Ignition on) , the ignition will be
switched off automatically after one hour.
To switch the ignition back on, turn the key
to position 1 (Stop), then back to position 2
(Ignition on) .
Starting / Switching off the
engine with Keyless Entry
and Starting
The electronic key must be present in the
passenger compartment.
If it is not detected, a message is displayed.
Move the electronic key so that the engine
can be started or switched off.
If there is still a problem, refer to the "Key
not detected - Back-up starting or Back-up
switch-off" section.

94
Driving
► Push forwards to shift down a gear.The gearbox only changes gear if the road
speed and engine speed permit; apart from
this condition, the rules for automatic operation
temporarily apply.
D disappears, and the gears engaged appear in
succession on the instrument panel.
If the engine speed is too low or too high, the
selected gear flashes for a few seconds, then the
gearactually activated is displayed.
It is possible to change from position D to
position M
at any time.When the vehicle is stationary or moving
very slowly, the gearbox selects gear M1
automatically.
The Sport and Snow programmes are inactive
in manual operation.
This symbol is displayed if a gear is not engaged correctly (gear selector between
two positions).
Switching off the vehicle
Before switching off the engine, it is possible to
engage position P or N to place the gearbox in
neutral.
In both cases, apply the parking brake to
immobilise the vehicle.
If the gear selector is not in position P,
when the driver's door is opened or
approximately 45 seconds after the ignition is
switched off, an audible signal sounds and a
message appears.
► Return the gear selector to P; the audible
signal stops and the message disappears.
Malfunction
In the event of a malfunction, this warning lamp comes on and a message is
displayed, when the ignition is switched on.
In this case, the gearbox goes into back-up
mode and is locked in 3
rd gear. It is possible to
feel a significant jolt (without risk for the gearbox)
while changing from P to R and from N to R.Do not exceed 62 mph (100 km/h), local speed restrictions permitting.
Have it checked by a CITROËN dealer or a
qualified workshop.
There is a risk of damaging the gearbox:– If the accelerator and brake pedals are pressed simultaneously.– In the event of a battery failure, forcing the selector from position P to another position.
With an automatic gearbox, never try to
start the engine by pushing the vehicle.
Gear efficiency indicator
(Depending on engine.)
This system helps reduce fuel consumption by
recommending the most appropriate gear.
Operation
Depending on the driving situation and the
vehicle's equipment, the system may advise to
skip one or more gears.
Gear shift recommendations should not be
considered compulsory. In fact, the road layout,
the traffic density and safety remain the deciding
factors when choosing the best gear. The driver
therefore remains responsible for deciding
whether or not to follow the indications issued by
the system.
This function cannot be deactivated.
With an automatic gearbox, the system is
only active in manual operation.
The information appears in the instrument panel, in the form of an arrow and the
recommended gear.
The system adapts its gear shift recommendation according to the driving
conditions (slope, load, etc.) and the driver’s
requirements (power, acceleration, braking,
etc.).
The system never suggests:
– engaging first gear;– engaging reverse.
Hill start assist
This system keeps your vehicle briefly stationary (for approximately 2 seconds) when making a hill
start, while you transfer your foot from the brake pedal to the accelerator pedal.
This system is only active when:
– The vehicle is completely stationary, with your foot on the brake pedal.– Certain slope conditions are met.– The driver’s door is closed.
Do not leave the vehicle while it is being
held temporarily by hill start assist.
If someone needs to get out of the vehicle
with the engine running, apply the parking
brake manually. Then check that the parking
brake indicator lamp is on fixed in the
instrument panel.
The hill start assist function cannot be deactivated. However, use of the parking
brake to immobilise the vehicle interrupts its
operation.
Operation

95
Driving
6start, while you transfer your foot from the brake
pedal to the accelerator pedal.
This system is only active when:
– The vehicle is completely stationary, with your foot on the brake pedal.– Certain slope conditions are met.– The driver’s door is closed.
Do not leave the vehicle while it is being
held temporarily by hill start assist.
If someone needs to get out of the vehicle
with the engine running, apply the parking
brake manually. Then check that the parking
brake indicator lamp is on fixed in the
instrument panel.
The hill start assist function cannot be deactivated. However, use of the parking
brake to immobilise the vehicle interrupts its
operation.
Operation

Facing uphill, with the vehicle stationary,
the vehicle is held for a short time when you
release the brake pedal:
– provided you are in first gear or neutral with a manual gearbox.– provided you are in mode D or M with an
automatic gearbox.


Facing downhill, with the vehicle stationary
and reverse gear engaged, the vehicle is held
for a short time when you release the brake
pedal.
Malfunction
This warning lamp comes on in the event of a malfunction, accompanied by an onscreen message.
Contact a CITROËN dealer or a qualified
workshop to have the system checked.
Stop & Start
The Stop & Start function puts the engine temporarily into standby - STOP mode - during phases when the vehicle is stopped (red lights,
queues, etc.). The engine restarts automatically
- START mode - as soon as the driver wishes to
move off again.
Primarily designed for urban use, the function
is intended to reduce fuel consumption and
exhaust emissions as well as the noise level
when stationary.
The function does not affect the functionalities of
the vehicle, in particular the braking.
Deactivation/Reactivation
The function is activated by default when the
ignition is switched on.
With / Without audio system


► Press the button.A message in the instrument panel confirms the
change of status.
When the function is deactivated, the orange
indicator lamp is lit; if the engine was in standby,
it restarts immediately.

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Driving
With the touch screen button
It is set via the Driving / Vehicle touch
screen menu.
A message in the instrument panel confirms the
change of status.
When the function is deactivated, if the engine
was in standby, it restarts immediately.
Associated indicator lamp
Function activated.
Opening the bonnet
Before doing anything under the bonnet,
deactivate the Stop & Start system to avoid
any risk of injury caused by the engine
restarting automatically.
Driving on flooded roads
Before entering into a flooded area, it is
strongly recommended that you deactivate
the Stop & Start system.
For more information on Driving
recommendations, particularly on flooded
roads, refer to the corresponding section.
Operation
Main conditions for operation
– The driver ’s door must be closed.– The driver's seat belt must be fastened.– The state of charge of the battery must be sufficient.– The temperature of the engine must be within its nominal operating range.– The outside temperature must be between 0°C and 35°C.
Putting the engine into standby
(STOP mode)
The engine automatically enters standby mode
as soon as the driver indicates their intention to
stop.
– With a manual gearbox: with the gear lever in
neutral and the clutch pedal released.
– With an automatic gearbox: with the gear
selector in position D or M, the brake pedal
depressed until the vehicle stops or the gear
selector in position N, with the vehicle stationary.
Time counter
A time counter adds up the time spent in standby
during the journey. It is reset to zero every time
the ignition is switched on.
Special cases:
The engine will not go into standby if all of the
conditions for operation are not met and in the
following cases.
– Steep slope (ascending or descending).– Vehicle has not exceeded 6 mph (10 km/h) since the last engine start (with the key or the
“START/STOP” button).
– Needed to maintain a comfortable temperature in the passenger compartment.– Demisting active.– Braking assistance being used.In these cases, this indicator lamp flashes for a few seconds, then goes off.
After the engine has restarted, STOP
mode is not available until the vehicle
has reached a speed of 5 mph (8 km/h).
During parking manoeuvres, STOP mode
is not available for a few seconds after
coming out of reverse gear or turning the
steering wheel.
Engine restarting (START mode)
The engine automatically restarts as soon as the
driver indicates the intention of moving off again.
► With a manual gearbox : with the clutch
pedal fully depressed.
► With an automatic gearbox :• With the selector in position D or M: with the
brake pedal released.
• With the selector in position N and the brake
pedal released: with the selector at D or M.
• With the selector in position P and the brake
pedal depressed: with the selector at R, N,
D or M.
• Reverse gear engaged.
Special cases
The engine will restart automatically if all
conditions for operation are met again and in the
following cases.
– Vehicle speed exceeds 2 mph (3 km/h).– Some specific conditions (braking assistance, air conditioning setting, etc.).In these cases, this indicator lamp flashes for a few seconds, then goes off.
Malfunctions
In the event of a malfunction, the button’s
indicator lamp flashes briefly, then remains on.
Have the vehicle checked by a CITROËN dealer
or a qualified workshop.
The vehicle stalls in STOP mode
All of the instrument panel warning lamps come
on if there is a fault.
► Switch off the ignition then start the engine again with the key or the " START/STOP" button.
The Stop & Start system requires a 12 V battery of specific technology and
specification.
All work concerning the battery must be
carried out only by a CITROËN dealer or a
qualified workshop.

97
Driving
6• With the selector in position P and the brake
pedal depressed: with the selector at R, N,
D or M.
• Reverse gear engaged.
Special cases
The engine will restart automatically if all
conditions for operation are met again and in the
following cases.
– Vehicle speed exceeds 2 mph (3 km/h).– Some specific conditions (braking assistance, air conditioning setting, etc.).In these cases, this indicator lamp flashes for a few seconds, then goes off.
Malfunctions
In the event of a malfunction, the button’s
indicator lamp flashes briefly, then remains on.
Have the vehicle checked by a CITROËN dealer
or a qualified workshop.
The vehicle stalls in STOP mode
All of the instrument panel warning lamps come
on if there is a fault.
► Switch off the ignition then start the engine again with the key or the "START/STOP" button.
The Stop & Start system requires a 12 V battery of specific technology and
specification.
All work concerning the battery must be
carried out only by a CITROËN dealer or a
qualified workshop.
Under-inflation detection
This system automatically checks the pressures of the tyres while driving.
It compares the information given by the wheel
speed sensors with reference values, which
must be reinitialised every time the tyre
pressures are adjusted or a wheel changed.
The system triggers an alert as soon as it
detects a drop in the inflation pressure of one or
more tyres.
Under-inflation detection does not
replace the need for vigilance on the part
of the driver.
This system does not avoid the need to
regularly check the tyre pressures (including
the spare wheel) as well as before a long
journey.
Driving with under-inflated tyres, particularly
in adverse conditions (heavy load, high
speed, long journey):
– worsens road-holding.– lengthens braking distances.
– causes premature wear of the tyres.– increases fuel consumption.
The inflation pressures defined for the vehicle can be found on the tyre pressure
label.
For more information on the Identification
markings, refer to the corresponding section.
Checking tyre pressures
This check should be done when the
tyres are "cold" (vehicle stopped for 1 hour or
after a journey of less than 6 miles (10 km) at moderate speeds).
Otherwise, add 0.3 bar to the pressures
shown on the label.
Snow chains
The system does not have to be
reinitialised after fitting or removing snow
chains.
Under-inflation alert
This is signalled by the fixed illumination of this warning lamp, accompanied by an
audible signal and, depending on equipment, the
display of a message.
► Reduce speed immediately , avoid excessive steering movements and avoid sudden braking.► Stop the vehicle as soon as it is safe to do so.
The loss of pressure detected does not
always cause visible bulging of the tyre.
Do not rely on just a visual check.
► Using a compressor , such as the one in the temporary puncture repair kit, check the
pressures of the four tyres when cold.
► If it is not possible to make this check immediately, drive carefully at reduced speed.

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Driving
► press button 5 again to save the suggested
speed.
The speed is immediately displayed as the new
speed setting on the instrument panel.
Temporarily exceeding the
speed setting
► Press the accelerator pedal down fully .The speed limiter is deactivated temporarily and
the displayed speed setting flashes.
► Release the accelerator pedal to return to below the programmed speed.
When the limit speed is exceeded but this is not
due to action by the driver (in case of a steep
slope, for example), an audible signal triggers
immediately.
On a steep descent or in the event of
sharp acceleration, the speed limiter will
not be able to prevent the vehicle from
exceeding the speed setting.
Brake if necessary to control the speed of
your vehicle.
Once the speed of the vehicle returns to the
programmed setting, the speed limiter functions
again: the display of the speed setting becomes
fixed again.
Switching off
► Turn the thumbwheel 1 to the "OFF" position:
the display of information on the speed limiter
disappears.
Malfunction

The display of dashes (flashing then fixed)
indicates a fault with the speed limiter.
Have it checked by a CITROËN dealer or a
qualified workshop.
Cruise control - particular
recommendations
For the safety of everyone, only use the
cruise control where the driving
conditions allow running at a constant speed
and keeping an adequate safety distance.
Remain vigilant when the cruise control
is activated. If you hold one of the speed
setting modification buttons down, a very
rapid change in the speed of your vehicle may
occur.
When descending a steep hill , the cruise
control system cannot prevent the vehicle
from exceeding the set speed. Brake if
necessary to control the speed of your
vehicle.
On steep climbs or when towing, the set
speed may not be reached or maintained.
Exceeding the programmed speed
setting
You can temporarily exceed the speed
setting by pressing the accelerator pedal (the
programmed speed flashes).
To return to the speed setting, release the
accelerator pedal (when the set speed is
reached again, the displayed speed stops
flashing).
Operating limits
Never use the system in the following
situations:
– In an urban area with the risk of pedestrians crossing the road.– In heavy traffic.– On winding or steep roads.– On slippery or flooded roads.– In poor weather conditions.– Driving on a speed circuit.– Driving on a rolling road.– When using snow chains, non-slip covers or studded tyres.
Cruise control
Refer to the General recommendations on the
use of driving and manoeuvring aids and to
Cruise control - particular recommendations.
This system automatically keeps the vehicle’s speed at the cruise value
programmed by the driver (speed setting), without using the accelerator pedal.
The cruise control is switched on manually.
It requires a minimum vehicle speed of 25 mph
(40 km/h).With a manual gearbox, third gear or higher must
be engaged.
With an automatic gearbox, mode D or second gear or higher in mode M must be engaged.
The cruise control remains active after changing gear, regardless of the gearbox
type, on engines fitted with Stop & Start.
Switching off the ignition cancels any
speed setting.
Steering mounted control

1. ON (CRUISE position) / OFF
2. Activate cruise control at the current speed /
decrease speed setting

109
Driving
6

This system:– warns the driver that their vehicle is at risk of collision with the vehicle in front or a pedestrian.– reduces the vehicle's speed to avoid a collision or limit its severity.
This system is comprised of three functions:
– Collision Risk Alert.
– Intelligent emergency braking assistance.– Active Safety Brake (automatic emergency braking).

The vehicle has a camera located at the top of
the windscreen.
This system does not avoid the need for
vigilance on the part of the driver.
This system is designed to assist the driver
and improve road safety.
It is the driver's responsibility to continuously
monitor the state of the traffic, observing the
driving regulations.
As soon as the system detects a potential obstacle, it prepares the braking
circuit in case automatic braking is needed.
This may cause a slight noise and a slight
sensation of deceleration.
Deactivation / Activation
By default, the system is automatically activated
at every engine start-up.
The system can be deactivated or activated via
the vehicle settings menu.
Deactivation of the system is signalled by the illumination of this indicator lamp,
accompanied by the display of a message.
Without audio system
► In the "DRIVE ASSIST" menu on the
instrument panel display, activate/deactivate
"COLLISION ALT" (Automatic emergency
braking).
With audio system
► In the "Personalisation-
configuration " menu, activate/deactivate
"Auto. emergency braking".
With touch screen
► In the Driving / Vehicle menu, select
the "Vehicle settings" tab, then
"Security" and activate/deactivate " Automatic
emergency braking".
Operating conditions and
limits
ESC system in working order.
ASR system activated.
Seat belts fastened for all passengers.
Stabilised speed on unwinding roads.
In the following cases, deactivating the system
via the vehicle's configuration menu is advised:
– Towing a trailer.– Carrying long objects on roof bars.– Vehicles with snow chains fitted.– Before using an automatic car wash, with the engine running.– Before placing the vehicle on a rolling road in a workshop.– Towed vehicle, engine running.– When a "space-saver" type spare wheel is fitted (depending on version).– If the brake lamps are not working.– Following impact to the windscreen close to the detection camera.
It is possible that warnings are not given,
are given too late or seem unjustified.
The driver must always stay in control of the
vehicle and be prepared to react at any time
to avoid an accident.
After an impact, the function automatically stops operating. Contact a
CITROËN dealer or a qualified workshop to
have the system checked.